열분해 튜브의 내면침탄에 따른 열응력 및 변형해석에 관한 연구 = A Study on the Thermal Stress and Deformation Analysis of Carburized Pyrolysis Tubes

다국어 초록 (Multilingual Abstract)

Ethylene is produced from a mixture of hydrocarbon feedstock and steam in a pyrolysis tubes. These pyrolysis tubes operating at high temperatures are subject to severe thermal stress, where carbon and/or carbon product get attached to the inner surface of the tubes.
This phenomena in duces a localized temperature increase, which in turn enhances a local carburization process. Additional stress is produced due to localized volume expansion, and the change in thermal expansion coefficient.
The carburization process eventually gives rise to building, bowing and crack of the pyrolysis tubes which therefore is known to be most critical process that decides the lifetime of the tubes. In this thesis, two dimensional analysis of the thermal stress and strain in the HK-40 pyrolysis tubes with varying carburization depths and was made using finite element methods. A commercially available NISA Ⅱ program was used on 16 different carburization models.